This book contains multiple chapters discussing some of the hot topics of Microbiology, including the role of the gut microbiota on allergies, the variety of man-related microbial activities, such as attenuated bacterial strains and vaccines, diseases and several syndromes conducting to obesity, as well as how microbiology can help in oil prospection and how this offers many opportunities for microbiologists. This text is for students of Microbiology, microbiologists themselves, and is written in a way that anyone less familiar with the field, but still interested in the topics it explores, can access the information in this book.